Whether or not New Yorkers agree with Mayor Bloomberg’s ideas, they can all agree that few mayors have taken as active an interest in the city’s schools as he has. His first term was marked by a restructuring of the public school bureaucracy, as the mayor and his chancellor, Joel Klein, tried to wrest more power out the hands of ossified middle managers, introducing unprecedented centralization into the system. Now they appear ready to hand some more authority back to principals – along with accountability. Such could be the thrust of an announcement Mr. Klein is slated to make today, as our Deborah Kolben reports this morning.

Such “devolution,” to use the word of one of the consultants Mr. Klein has brought in to help with his latest reform efforts, is in one sense a natural progression in the mayor’s reform efforts. Mr. Bloomberg spent his first term reining in an unruly bureaucracy that was more interested in preserving the status quo than it was in education. Changing deeply ingrained habits required a strong leader to seize control, which is what the mayor and the chancellor did.

Mr. Bloomberg understands that such a centralized structure isn’t any way to run a business over the long term. That partly explains his enthusiasm for charter schools; a charter, publicly funded but free to make its own rules, is a decentralized public school. Now that he has broken some eggs in the system, it’s time to make the omelet – to implement a sustainable structure. We’d like to think that the mayor and chancellor are not backtracking on their earlier work so much as taking the next step forward.

The decentralizing, if done well, could be a boon for the city’s schools. If Messrs. Bloomberg and Klein can succeed in providing principals with strong incentives to succeed and the latitude to implement the best teaching methods for their students, the city could be in for educational greatness. Yet it is likely to prove a lot harder than it sounds to do that.

“Providing incentives,” to both principals and teachers, will difficult in the face of a union contract that makes it impossible for principals to extend the school day or for administrators to reassign or fire bad teachers, for example. The mayor and chancellor are up against a system that has done a masterful job of insulating itself from any and all incentives, and their mixed results on work rules in the last teachers’ contract negotiation highlight the intractability of the problem.

No doubt, too, that the mayor and chancellor realize the importance of greater accountability at the school level. They apparently think they will be able to craft a management structure that will impose that accountability. We wish them nothing but luck, though there is still the whole question of curriculum. In the long run the best thing the mayor, chancellor, or legislature could do is open the system to the competition that would come with a real voucher program or tuition tax credits. If accountability is the goal, school choice – going far beyond the excellent start with charters – is the logical centerpiece of the reform. The mayor and chancellor will only ever be partly successful in their management reforms if they don’t also introduce accountability by giving parents a compelling voice in education.